To provide an effective defense against tanks and other armored vehicles, the need arises for ammunition capable of penetrating armor plating. This is commonly referred to as armor-piercing ammunition. In order for an armor-piercing round to be effective, a high impact velocity of the projectile against the armored target is required. It then follows that high muzzle velocities, i.e., velocities of the projectile leaving the gun barrel or tube, are necessary to provide the required impact velocity. One method of obtaining such high muzzle velocity is by the use of what is referred to as explosive drivers. These utilize the energy of burning propellant to compress light gases into a high energy reservoir while the projectile is still in the gun tube. The gases then act on the projectile causing it to accelerate to a very high muzzle velocity. This concept provides significantly higher muzzle velocities than conventional ammunition.
Prior art drivers incorporated a central cylinder of propellant encased in a liner. The light gas would then occupy the space surrounding the liner within the outer casing. When the round is detonated, the burning propellant expands the liner outwardly against the case to compress the gas. As the liner contacts the casing the residual energy is transferred to it and therefore wasted.
In this concept the ammunition package is contained in a long slender cylinder. This leads to increased length of the weapon system to accommodate such a round.
The weapon system is best kept to a minimum length in order to be manufactured economically and to provide a weapon that can be more easily transported.